Not sure why you insist that the only purpose of tactical advantage is to buff your first unit, if that was the sole purpose, it would buff it the moment you play the first unit. Tactical advantage can be played several ways, you can use it to protect your first unit, or you can wait for some damaged unit so it does not buffs it over 7, or you can use it to gain (or deny) dominance, or to protect a later engine after you baited their tall removal...
Who said it was?
I sure didn't. But if you use it on the first unit, on any decent unit it will protect that unit from any bronze card or any cheap card, except predatory dive. if someone wants to take out my tactical advantage unit with an expensive gold card, that's fair enough. But predatory is a cheap bronze card.
I don't know how anyone can disagree with this, unless they use predatory dive themselves and want to "protect" the card from being defect.
The card says: "
each player destroys their lowest unit". That's cheasy enough with a deathwish card. A 5 point bronze card does not to go way out over it's own scope. Predatory dive has been problematic for a long time, and it was highly noticeable just how defect that card is during the time people played "no-units" decks. That problem has not gone away.
I would still not be fine with the card saying "each player destroys their lowest unit, if you have no unit, scorch the enemy unit". That's just not reasonable for a 5 provision card. I also think the card does not need more scorch style (destroy) cards. There are plenty already, and I certainly don't think a bronze card should be able to work as one. I think the game would be better off if it made epidemic into a gold card (it's already high provision), and removed the "new scorch" card "curse of corruption" or changed it into something not scorch related. But that's way outside the scope of this discussion.
Predatory dive is defect according to it's own description, and it's anti-tactical advantage and undoubtedly way out of scope from it's original intention. Ooh, and did I mention that is is a 5 provision bronze?